I was diagnosed after a couple of five minute appointments with a psychiatrist, though he did have my notes from before (but it had been seen as recurrent depression previously). I wasn't told at the time, and found out months later after my GP accidentally let me see the computer screen! It's a bit unfortunate that I wasn't told when I was diagnosed, because by the time I found out, I was no longer seeing a psychiatrist or receiving any mental health support, so I haven't been able to have anyone explain it properly to me.

I am obviously not qualified to say whether or not it's accurate, but I do have doubts.